Bariatrics is the field of medicine encompassing the study of overweight, its causes, prevention and treatment. Bariatric surgery is a treatment for morbid obesity that involves alteration of a patient's digestive tract to encourage weight loss and to help maintain normal weight. The following history of bariatric surgery is provided by the American Society for Bariatric Surgery.
JEJUNO-ILEAL BYPASS: Kremen and Linner's Jejuno-ileal Bypass: Bariatric surgery has continually evolved since its initial sporadic and tentative introduction in the 1950's. The first bariatric procedure to be preceded by animal studies and subsequently presented to a recognized surgical society and published in a peer-reviewed journal was that of Kremen and associates in 1954. (Kremen, Linner et al. 1954) The case, which they presented, was of a jejuno-ileal bypass (JIB). Jejuno-ileal bypass involved joining the upper small intestine to the lower part of the small intestine, bypassing a large segment of the small bowel, which is thus taken out of the nutrient absorptive circuit. In the discussion of the case, Philip Sandblom of Lund, Sweden, alluded to the fact that, two years previously, Victor Henriksson of Gothenberg, Sweden, had performed a similar procedure for morbid obesity. In this case the redundant small bowel was excised rather than bypassed. Subsequently it was discovered that Dr. Richard Varco of the University of Minnesota independently performed JIB at the University of Minnesota Hospitals around the same time as the operation of Kremen et al. Varco's case was unpublished and the patient record lost, so that the exact procedure date is unknown. (Buchwald and Rucker 1984)
JEJUNO-COLIC BYPASS: As part of an ongoing study of morbid obesity, Payne et al. reported results of ten patients in whom an end-to-side jejuno-colic shunt had been performed. (Payne, DeWind et al. 1963) In jejuno-colic shunt, the upper small bowel was joined even further down the intestinal tract, to the colon, with the idea of bypassing an even longer segment of the nutrient absorptive gastrointestinal tract. These patients had episodes of uncontrollable diarrhea, dehydration and electrolyte imbalance. Because of the problem with diarrhea, most of these surgeries were eventually taken down and converted to end-to-side jejuno-ileostomies. Payne and Dewind subsequently advised against jejunocolic anastomoses, instead recommending end-to-side jejuno-ileostomy anastomosing the first 14 inches of jejunum to the last 4 inches of ileum. (Payne and DeWind 1969)
PROBLEMS WITH JEJUNO-ILEAL BYPASS: (JIB) Two variants of jejunoileal anastomosis were developed, the end-to-side (Payne and DeWind 1969) and end-to end (Scott, Dean et al. 1973) anastomoses of the proximal jejunum to distal ileum. In both instances an extensive length of small intestine was bypassed, not excised, excluding it from the alimentary stream.
In both these variants a total of only about 35 cm (18″) of normally absorptive small intestine was retained in the absorptive stream, compared with the normal length of approximately 7 meters (twenty feet). In consequence, malabsorption of carbohydrate, protein, lipids, minerals and vitamins inevitably occur, Where the end-to-side technique was used, reflux of bowel content back up the defunctionalized small intestine allowed absorption of some of the refluxed material resulting in less weight loss initially and greater subsequent weight regain.
Bile is secreted by the liver, enters the upper small intestine by way of the bile duct, and is absorbed in the small intestine. Bile has an important role in fat digestion, emulsifying fat as the first stage in its digestion. Bypassing the major site of bile acid reabsorption in the small intestine therefore further reduces fat and fat soluble vitamin absorption. As a result, huge amounts of fatty acids, which are normally absorbed in the small intestine, enter the colon where they cause irritation of the colon wall and the secretion of excessive volumes of water and electrolytes, especially sodium and potassium, leading to diarrhea. This diarrhea is the major patient complaint and has characterized jejunoileal bypass in the minds of patient and physician alike since the procedure was introduced.
Bile salts help to keep cholesterol in solution in the bile. Following JIB, the bile salt pool is decreased as a consequence of reduced absorption in the small intestine and bile salt losses in the stool. The relative cholesterol concentration in gallbladder bile rises and cholesterol crystals precipitate in the gallbladder bile, forming a nidus for development of cholesterol gallstones in the gallbladder. Specific vitamin deficiencies also occur; Vitamin D and Calcium deficiencies lead to thinning of bone with bone pain and fractures as a result of osteoporosis and osteomalacia. Bypass of the terminal ileum, which is the specific site of Vitamin B12 absorption, leads to Vitamin B12 deficiency with a specific peripheral neuropathy. Vitamin A deficiency can induce night blindness. Calcium Oxalate renal stones occur commonly following JIB, along with increased colonic absorption of oxalate. The colonic absorption of oxalate has been attributed to:
1. Exposure of colonic mucosa to excessive bile salts and possibly bile acids, increasing colonic permeability to oxalate, or
2. Excessive quantities of fatty acids in the gut form soaps with calcium, reducing its availability to form insoluble calcium oxalate leading to the persistence of soluble and absorbable oxalate in the colon.
Patients with intestinal bypass develop diarrhea 4-6 times daily. The frequency of stooling varying directly with fat intake. There is a general tendency for stooling to diminish with time, as the short segment of small intestine remaining in the alimentary stream increases in size and thickness, developing its capacity to absorb calories and nutrients, thus producing improvement in the patients nutrition and counterbalancing the ongoing weight loss. This happy result does not occur in every patient, but approximately one third of those undergoing “Intestinal Bypass” have a relatively benign course. Unfortunately, even this group is at risk of significant late complications, many patients developing irreversible hepatic cirrhosis several years after the procedure.
JIB is the classic example of a malabsorptive weight loss procedure. Some modern procedures utilize a lesser degree of malabsorption combined with gastric restriction to induce and maintain weight loss. Any procedure involving malabsorption must be considered at risk to develop at least some of the malabsorptive complications exemplified by JIB. The multiple complications associated with JIB while considerably less severe than those associated with Jejunocolic anastomosis, were sufficiently distressing both to the patient and to the medical attendant to cause the procedure to fall into disrepute.
Listing of jejuno-ileal bypass complications:
Mineral and Electrolyte Imbalance:
Decreased serum sodium, potassium, magnesium and bicarbonate
Decreased sodium chloride
Osteoporosis and osteomalacia secondary to protein depletion, calcium and vitamin D loss, and acidosis
Protein Calorie Malnutrition:
Hair loss, anemia, edema, and vitamin depletion
Cholelithiasis
Enteric Complications:
Abdominal distension, irregular diarrhea, increased flatus, pneumatosis intestinalis, colonic pseudo-obstruction, bypass enteropathy, volvulus with mechanical small bowel obstruction
Extra-intestinal Manifestations:
Arthritis
Liver disease, occurs in at least 30%
Acute liver failure may occur in the postoperative period, and may lead to death acutely following surgery.
Steatosis, “alcoholic” type hepatitis, cirrhosis, occurs in 5%, progresses to cirrhosis and death in 1-2%
Erythema Nodosum, non-specific pustular dermatosis
Weber-Christian Syndrome
Renal Disease:
Hyperoxaluria, with oxalate stones or interstitial oxalate deposits, immune complex nephritis, “functional” renal failure.
Miscellaneous:
Peripheral neuropathy, pericarditis, pleuritis, hemolytic anemia, neutropenia, and thrombocytopenia
The multiple complications associated with JIB led to a search for alternative procedures, one of which was gastric bypass, a procedure that is described in detail later. In 1983 Griffen et al. reported a comprehensive series comparing the results of jejuno-ileal bypass with gastric bypass. 11 of 50 patients who underwent JIB required conversion to gastric bypass within 5 years, leading Griffen to abandon jejuno-ileal bypass. (Griffen, Bivins et al. 1983)
JIB can be summed up as having:
a. Good Weight Loss,
b. Malabsorption with multiple deficiencies,
c. Diarrhea.
As a consequence of all these complications, jejuno-ileal bypass is no longer a recommended Bariatric Surgical Procedure. Indeed, the current recommendation for anyone who has undergone JIB, and still has the operation intact, is to strongly consider having it taken down and converted to one of the gastric restrictive procedures.
BILIOPANCREATIC DIVERSION: A modern variant of the Jejuno-ileal Bypass (JIB) is Biliopancreatic Diversion (BPD), a procedure that differs from JIB in that no small intestine is defunctionalized and, consequently, liver problems are much less frequent. This procedure was developed by Professor Nicola Scopinaro, of the University of Genoa, Italy. (Scopinaro, Gianetta et al. 1996)
This procedure has two components. A limited gastrectomy results in reduction of oral intake, inducing weight loss, especially during the first postoperative year. The second component of the operation, construction of a long limb Roux-en-Y anastomosis with a short common “alimentary” channel of 50 cm length. This creates a significant malabsorptive component that acts to maintain weight loss long term. Dr. Scopinaro recently published long-term results of this operation, reporting 72% excess body weight loss maintained for 18 years. These are the best results, in terms of weight loss and duration of weight loss, reported in the bariatric surgical literature to this date.
From the patient's perspective, the great advantages of this operation are the ability to eat large quantities of food and still achieve excellent, long-term weight loss results. Disadvantages of the procedure are the association with loose stools, stomal ulcers, and foul smelling stools and flatus. The most serious potential complication is protein malnutrition, which is associated with hypoalbuminemia, anemia, edema, asthenia, alopecia, generally requires hospitalization and 2-3 weeks hyperalimentation. BPD patients need to take supplemental calcium and vitamins, particularly Vitamin D, lifelong. Because of this potential for significant complications, BPD patients require lifelong follow-up. In BPD patients who have received 200-300 cm alimentary limbs because of protein malnutrition concerns, the incidence of protein malnutrition fell dramatically to range from 0.8% to 2.3%.
In 1988, Hess, using a combination of Scopinaro's BPD and the duodenal switch described by DeMeester in 1987, developed a hybrid operation with the advantages of the BPD, but without some of the associated problems. The duodenal switch, originally designed for patients with bile reflux gastritis, consists of a suprapapillary Roux-en-Y duodeno-jejunostomy. This allows the first portion of the duodenum to remain in the alimentary stream thus reducing the incidence of stomal ulcer. When combined with a 70%-80% greater curvature gastrectomy (sleeve resection of the stomach) continuity of the gastric lesser curve is maintained while simultaneously reducing stomach volume. A long limb Roux-en-Y is then created. The efferent limb acts to decrease overall caloric absorption and the long biliopancreatic limb diverting bile from the alimentary contents, specifically to induce fat malabsorption. This technique, was first presented by Hess in 1992 and first published in a paper by Marceau, Biron et al. in 1993 is known as Biliopancreatic Diversion with Duodenal Switch (BPDDS). This procedure is claimed to essentially eliminate stomal ulcer and dumping syndrome.
BPD and its variants are the most major procedures performed for obesity and it follows that prospective patients who wish to consider BPD should seek out experienced surgeons with life-long follow up programs.
Listing of complications of biliopancreatic diversion:
Protein Malnutrition 15%
Incisional hernia 10%
Intestinal obstruction 1%
Acute biliopancreatic limb obstruction Stomal Ulcer 3.0%
Bone Demineralization: Pre-op 25%; at 1-2 yrs, 29%; at 3-5 yrs 53%; at 6-10 yrs 14%.
Hemorrhoids 4.3%
Acne 3.5%
Night Blindness 3%
Operative Mortality 0.4%-0.8% (1122 subjects, 1984-1993)
GASTRIC BYPASS: Gastric Bypass (RGB) was developed by Dr. Edward E. Mason, of the University of Iowa, based on the observation that females who had undergone partial gastrectomy for peptic ulcer disease, tended to remain underweight following the surgery, and that it was very difficult to achieve weight gain in this patient group. He therefore applied the principles of partial gastrectomy to obese females, finding that they did indeed lose weight. (Mason and Ito 1967) With the availability of surgical staples, he was able to create a partition across the upper stomach using staples, and did not require removal of any of the stomach. Subsequent modifications of the technique include a pouch of 50 ml or less, a gastroenterostomy stoma of 0.9 mm, use of the Roux-en-Y technique to avoid loop gastroenterostomy and the bile reflux that may ensue. Lengthening of the Roux limb to 100-150 cm to include a greater element of malabsorption and improve weight loss and the use of the retrocolic and retrogastric routing of the gastrojejunostomy to ease the technical difficulties of the procedure and improve long term weight loss results. Staple line failures have been found to occur many years after the procedure, in consequence surgeons have responded by use of techniques designed to prevent this. These include transection of the stomach, in which the staple line is divided and the cut ends oversewn. An alternative technique using superimposed staple rows is claimed to exert its effect by crushing the stomach tissue causing firm scarring along the staple line. Additionally, there have been attempts to stabilize the gastroenterostomy by the use of a prosthetic band, fashioned into a ring positioned just above the junction of gastric pouch and small intestine. Gastric Bypass has also stood the test of time, with one series of greater than 500 cases, followed for 14 years, maintaining 50% excess weight loss.
The complications of gastric bypass are much less severe than those of Intestinal Bypass, and most large series report complications in two phases, those that occur shortly after surgery, and those that take a longer time to develop. The most serious acute complications include leaks at the junction of stomach and small intestine. This dangerous complication usually requires that the patient be returned to surgery on an urgent basis, as does the rare acute gastric dilatation, which may arise spontaneously or secondary to a blockage occurring at the Y-shaped anastomosis (jejunojejunostomy). Then there are the complications to which any obese patient having surgery is prone, these including degrees of lung collapse (atelectasis), which occur because it is hard for the patient to breathe deeply when in pain. In consequence a great deal of attention is paid in the postoperative period to encouraging deep breathing and patient activity to try to minimize the problem. Blood clots affecting the legs are more common in overweight patients and carry the risk of breaking off and being carried to the lungs as a pulmonary embolus. This is the reason obese patients are usually anticoagulated before surgery with a low dose of Heparin or other anticoagulant. Wound infections and fluid collections are quite common in morbidly obese patients. These complications are often exacerbated by the presence five or six inches of fatty tissue outside the muscle layers of the abdomen.
Complications that occur later on after the incision is all healed include narrowing of the stoma (the junction between stomach pouch and intestine), which results from scar tissue development. Recall that this opening is made about 10 mm in diameter, not much wider than dime. With an opening this small, a very little scarring will squeeze the opening down to a degree that affects the patient's eating. Vomiting which comes on between the 4th and 12th week may well be due to this cause. The problem can be very simply dealt with by stretching the opening to the correct size, by “endoscopic balloon dilatation”, which usually involves a single procedure on a day stay basis to correct the problem. Wound hernias occur in 5-10% and intestinal obstruction in 2% of patients an incidence similar to that following any general surgical abdominal procedure.
Another late problem that is fairly common, especially in menstruating women, after gastric bypass is anemia. Since the stomach is involved in iron and Vitamin B12 absorption, these may not be absorbed adequately following bypass. As a result anemia may develop. The patient feels tired and listless, and blood tests show low levels of hematocrit, hemoglobin, iron and Vitamin B12. The condition can be prevented and treated, if necessary, by taking extra iron and B12. Since the food stream bypasses the duodenum, the primary site of calcium absorption, the possibility of calcium deficiency exists, and all patients should take supplemental calcium to forestall this.
Dumping is often mentioned as a complication of gastric bypass, but it really is a side effect of the procedure caused by the way the intestine is hooked up. Dumping occurs when the patient eats refined sugar following gastric bypass, this causes symptoms of rapid heart beat, nausea, tremor and faint feeling, sometimes followed by diarrhea. Of course no one likes these feelings, especially patients who love sweets! The upshot is, of course, that sweet lovers avoid sweets after gastric bypass and this is a real help to them in their efforts to lose weight. It should be noted that a few surgeons, expert at endoscopic/laparoscopic surgery, are performing Gastric Bypass using laparoscopic techniques.
Listing of complications following gastric bypass:
Early:
1. Leak
2. Acute gastric dilatation
3. Roux-Y obstruction
4. Atelectasis
5. Wound Infection/seroma
Late:
1. Stomal Stenosis
2. Anemia
3. Vitamin B12 deficiency
4. Calcium deficiency/osteoporosis
Silastic Ring Gastric Bypass & Vertical banded gastric bypass (Fobi): The use of rings to control the stoma size, proven with Vertical Banded Gastroplasty, has led to their adoption by some surgeons as an addition to gastric bypass procedures, again to control the stoma size and prevent late stretching of the opening and, hopefully, improve the long term weight maintenance results. Both silastic rings and Marlex bands have been used. Usually the recommendation is for the ring circumference to be considerably larger than that used in primary obesity procedures, so that the limiting effect only comes into play after some degree of stretching of the pouch has occurred. The complications following silastic ring gastric bypass include the same complications as for gastric bypass, plus band erosion.
GASTROPLASTY: During World War II, the Russians, as part of their war effort, developed a series of surgical instruments to staple various body tissues together as a simple and rapid method of dealing with injuries. This concept was adapted and refined by American surgical instrument makers after the war, leading to the surgical stapling instruments in use today. These are capable of laying down as many as four parallel rows of staples, to create a partition, or the instrument comes with a knife blade which will cut between the newly placed staple rows, dividing and sealing the stapled tissues simultaneously. Other instruments place circular rows of staples to join two tubes end-to-end, which is very useful in connecting intestine together.
The early use of such stapling devices in obesity surgery involved removal of three staples from the row and firing the stapler across the top part of the stomach. This staples the two stomach walls together, except at the point where the three staples were removed, where a small gap remains. The idea being that food that the patient takes in is held up in the segment of stomach above the staple line causing the sensation of fullness. The food then empties slowly through the gap (stoma) into the stomach below the staple line where digestion takes place normally. Unfortunately, the muscular stomach wall has a tendency to stretch and the stoma enlarges. It soon became apparent that while patients lost weight for the first few months while the stoma was small, they soon stopped losing, and, indeed, frequently regained all they had lost. Surgeons tried to counter this by reinforcing the opening between the two compartments (Gomez 1981), however these techniques were only partially successful. The search for a better gastroplasty was pursued by Dr. Edward E. Mason, Professor of Surgery at the University of Iowa. (Mason 1982) He realized that the lesser curvature part of the stomach had the thickest wall and was therefore least likely to stretch, so he used a vertical segment of stomach along the lesser curvature for the pouch. Additionally, he was very meticulous in defining the size of the pouch, measuring it at surgery under a standard hydrostatic pressure, and has shown that best results follow the use of a very small pouch, holding only 14 cc saline at the time of surgery. The third modification that he made was to place a polypropylene band (Marlex Mesh) around the lower end of the vertical pouch, which acts as the stoma, to fix the size of the outlet of the pouch, preventing it from stretching. This is done by use of the circular stapling instrument to staple the front and back walls of the stomach together, cutting out a circular window to allow the polypropylene band to be placed around the lower end of the pouch. His extensive studies showed that the correct circumference of the band is 5.0 cm. The whole operation is called Vertical Banded Gastroplasty (VBG). Correctly performed this operation produces good weight loss results. It has the advantages of being a pure restrictive procedure with no malabsorption component and no dumping. Of course sweet eaters will have to avoid sweets on their own if they have this procedure. Similarly there are few complications associated with Vertical Banded Gastroplasty, because all food taken in is digested normally, and anemia is rare and Vitamin B12 deficiency is almost unknown. The patient does have to be very careful to chew food completely to avoid vomiting, and to avoid high calorie liquids such as regular sodas and ice cream that pass easily through the stoma. A surgical variant of the VBG is the Silastic Ring Vertical Gastroplasty (SRVG), which is functionally identical to VBG but uses a silastic ring to control the stoma size. It should be noted that a few surgeons, expert in minimal access surgery are performing gastroplasty using laparoscopic techniques.
Listing of complications following vertical banded gastroplasty:
Stenosis with persistent vomiting, if untreated, causing neurological damage
Ulcer
Incisional hernia
Wound Infection
Band erosion
Leakage (including post-operative leakage due to failure of the initial closure and late leakage due to staple line failure and/or failure of the stomach walls to heal/fuse together)
GASTRIC BANDING: Another way to limit food intake is to place a constricting ring completely around the top end (fundus) of the stomach, creating an hourglass effect. The ring is placed near the upper end of the stomach, just below the junction of stomach and esophagus. This idea of gastric banding has been around for quite a number of years, and was pursued in Europe and Scandinavia particularly. Initially, a readily available material such as arterial graft was used for the band. The results, however, were not as good as RGB or VBG and the concept has only become popular with the development of modern bands designed for the task and techniques to measure the size of the “stoma” created under the band and associated pressures. An ingenious variant, the inflatable band was developed by Dr. Kuzmak (Kuzmak, Yap et al. 1990) who devised a band lined with an inflatable balloon. This balloon was connected to a small reservoir that is placed under the skin of the abdomen, through which, the balloon can be inflated, thus reducing the size of the stoma, or deflated thus enlarging the stoma. Even more ingenious, has been the development of models that can be inserted laparoscopically, thus saving the patient the discomfort of a large incision. Since the hourglass configuration only constricts the upper stomach, with no malabsorptive effect, it acts as a pure restrictive operation. Like VBG, the favorable consequences are absence of anemia, dumping and malabsorption, while the disadvantages include the need for strict patient compliance. Long-term results of this device are not yet available, but logic would suggest they are likely to be comparable to VBG results with an unknown additional effect due to manipulation of the inflatable balloon. At the present time there are two devices on the world market. The LapBand manufactured by Bioenterics, Carpenteria, Calif. and the Obtech device produced in Sweden by Obtech Medical AG. Only the LapBand is freely available in the USA at this time, having completed U.S. trials and been approved for use by the FDA.
Listing of Complications Following Gastric Banding
Operative:
Splenic Injury
Esophageal Injury
Conversion to Open Procedure
Wound Infection
Late:
Band slippage
Reservoir deflation/leak
Failure to lose weight
Persistent vomiting
Acid reflux